About 1 in 8 women will suffer from breast cancer at some point in their life. When they do, the fear of recurrence is, understandably, great. It appears that this fear is leading to unnecessary prophylactic surgery for many. Specifically, many with minimal risk for the unaffected breast will have that breast removed. This is the conclusion of a new study presented at a recent symposium. Please note that this has not yet gone through the peer review process prior to publication in a journal, so the results should be viewed as preliminary.
Dr. Sarah Hawley and her colleagues surveyed 1,500 women who were previously treated for breast cancer and had gone 4 years without a recurrence. One aspect of their study was focused on what treatment and prophylaxis the women had chosen. About 7 percent of the women had a contralateral prophylactic mastectomy (CPM), where both the affected and unaffected breasts were removed. About 1 in 5 women having a mastectomy chose to have the unaffected breast removed also.
Now consider the risks. The risk of a recurrence in the affected breast is 8%, which why many choose to have the affected breast removed. However, as one of Dr. Hawley’s co-authors has said, “Breast cancer does not spread from one breast to another”. In other words, the risk to the unaffected breast is not from the current cancer, but strictly from a new primary cancer developing in that breast. That risk is about 1%.
Alas, it isn’t quite that simple. The risk to the unaffected breast is quite minimal for most women, but not for all. Some women have a high risk of breast cancer, and are at high risk for a new cancer developing in the other breast. This would include women who have a known BRCA gene mutation conferring very high risk of breast and ovarian cancer, or people with family history of breast or ovarian cancer. High risk due to family history is often based on having 2 or more immediate family members affected (mother, sisters, daughters). Women with these risk factors do not have minimal risk to the unaffected breast, and CPM makes sense for them. In Dr. Hawley’s study about 30% had increased risk of a new primary breast cancer.
However, for women without these risk factors, there is very minimal risk for a new primary breast cancer in the unaffected breast. These women made up about 70% of those who had the double mastectomy.
Let’s get some perspective about the numbers here. Overall, of all these women, about 7% had CPM, and 70% of these were in low risk women. That’s pretty bad. On the other hand, it is still only about 5% of the total patients. One might think, hey, 5% is pretty small. But, to put this into the proper context, let’s remember how this post started – about 1 in 8 women will have breast cancer at some point in their life. 5% of that number comes to close to 1 million women. That’s an awful lot of women who will have the other breast removed unnecessarily.
Some of these women were probably older, and the psychosocial impact of losing the 2nd breast may have been smaller. On the other hand, an older woman with minimal risk has fewer remaining years to get another new primary breast cancer, so it makes even less sense for them.
Why are so many women getting a mastectomy for breast cancer opting for removal of the unaffected breast? The obvious answer, of course, is fear. The real message of this study is:
Fight fear with education, not surgery.